The present invention relates to a reference voltage selection circuit, a display driver, an electro-optical device, an electronic instrument, and the like.
An electro-optical device represented by a liquid crystal display (LCD) panel has been widely provided in portable electronic instruments. An image display rich in color tone due to an increase in the number of grayscale levels is desired for an electro-optical device.
An image signal for displaying an image is generally gamma-corrected corresponding to the display characteristics of a display device. Taking an electro-optical device as an example, a reference voltage corresponding to grayscale data that determines the grayscale value is selected from a plurality of reference voltages, and the transmissivity of a pixel is changed based on the selected reference voltage. Therefore, gamma correction is implemented by changing the voltage level of each reference voltage.
The reference voltage is generated by dividing the voltage across a ladder resistor circuit using a plurality of resistor elements of the ladder resistor circuit. Therefore, the voltage level of each reference voltage can be changed by changing the resistance of each resistor element.
A more accurate gamma correction is desired in order to deal with an increase in resolution and diversification of LCD panels. JP-A-2006-227271 discloses a reference voltage selection circuit that implements gamma correction by a simple configuration, for example.
The reference voltage selection circuit disclosed in JP-A-2006-227271 suppresses an increase in circuit scale by forming switch elements for selectively outputting the reference voltage in a matrix. Moreover, an increase in circuit scale of the reference voltage selection circuit can be suppressed even if the number of reference voltages and the like increases.
As a result of studies on the reference voltage selection circuit and the technological idea disclosed in JP-A-2006-227271, it was found that reliability can be further improved by taking appropriate measures.